Point-of-care testing refers generally to medical testing at or near the site of patient care, such as in an emergency room. A desired outcome of such tests is often to obtain rapid and accurate lab results to determine a next course of action in patient care. A number of such point of care tests involve taking or otherwise using a blood sample from a patient. The ideal blood sample is pure plasma separated from the source whole blood sample. Hemolysis (haemolysis), however, is a common problem which may introduce undesirable components into the plasma fraction.
In particular, hemolysis refers to the rupturing of erythrocytes (red blood cells) and the release of their contents, including hemoglobin and potassium, into surrounding fluid (e.g., blood plasma). Hemolysis may occur in vivo or in vitro (inside or outside the body). During any of the collection, transportation, and handling of patient whole blood samples, there is the possibility of hemolysis. If hemolysis occurs, the resulting components in the sample may cause interference in a number of tests, thereby leading to a signal reduction, reduced measurement accuracy and precision, or to false positive results at the other end of the spectrum. Further, if hemolysis occurs, it has been found that the potassium concentration in a corresponding sample may increase significantly and cause a high risk of misdiagnosis in a diagnostic test for potassium levels. See Clinical Chemistry, December 2003, vol. 49, no. 12, 2105-2106. Current methods do not adequately and quickly determine whether an unacceptable level of hemolysis has occurred in a blood sample.